natgillin/translations-raw huggingface dataset:
Standards and/or reference materials Investigate blanks Artificially prepared samples (e.g. spiked) Statistics Common sense
9Etaloaneşi/sau materiale de referin 9Probe de ‘blank’ 9Probe preparate artificial (de ex. cu adaos)9No iunide statistic9Bun sim
Performance parameters of the procedure
Parametrii de performan ai procedurii
(qualitative): selectivity, specificity
�(calitativi): -selectivitatea şispecificitatea�(cantitativi): -domeniul (liniar) de lucru
– recovery – robustness
�incertitudinea, considerindde ex. – recuperarea - repetabilitatea – robustetea - reproductibilitatea
Selectivity refers to the extent to which the method can beused to determine particular analytes in mixtures or matriceswithout interferences from other components of similarbehaviour
•Selectivitatease referla msuraîncare metoda poate fi utilizatpentru a determina compuşi particularidin amestecuri sau din diferitematricifra interfera cu alti compuşi ce aucomportaresimilar
Specificity is 100% selectivity
•Specificitateaeste selectivitatea de 100%
IUPAC recommends that the term specificity should beavoided
•IUPAC recomandca termenul specificitatesfie evitat
Acid-base titration
Cromatografie acid-baza
Linearity Working Range
Liniaritatea Domeniul de Lucru
(e.g. contamination in digestion, purification)
(de ex. contaminarea prin digestie, purificare)
Signal = b
Semnal = b0
Ybl = Signal of the ‘blank’ ;sbl= stdev of the ‘blank’ in signal domain
Ybl sbl= abatereastandard a ‘blank-ului’ înunit i de semnal
Reporting of LOD
Raportarea LOD
Detection capability at low concentrations
Capabilitatea de detec iela concentra ii scazute
Not present
Nue prezent
Not detected
Ne-detectat
True Negative
Adevrat Negativ
False Negative
Fals Negativ n
Detected
Detectat o
True Positive
Fals Pozitiv
Insensitive method?
Adevrat Pozitiv n Metoda insensibil? Interferen e? o Interferen e? Contaminare
Decisions on LOD
Decizii asupra LOD
Non-presence of analyte
In absen a analitului
Presence of analyte cut-off
In prezen a analitului
Definition:The change in the response of a measuring instrumentdivided by the corresponding change in the stimulus
•Defini ie:Raportuldintremodificarearspunsuluiunuimijlocde msurareşischimbareacorespunztoarea semnaluluide intrare
What it means:The gradient (slope) of the calibration graph
•Ceînseamn: Gradientul(panta) curbeide etalonare
A measure of the trueness of a (measurement) procedure
O msura veridicit ii uneiproceduri(de msurare)
R= observed _ value reference _ value
R = valoarea _ de _ referinta
Reference value from:
Valoareade referin din:
The closer R is to 1, the smaller the bias in the procedure
Cu cât R estemaiapropiatde1, cu atât estemaimicbias-ulprocedurii
The recovery for a particular sample, R, consist of threecomponents combined multiplicatively (VAM Project 3.2.1):
Recuperareapentruo anumitprob,R, constîncombinareaprinmultiplicarea treicomponente(VAM Project 3.2.1):
Rm mean recovery obtained from the analysis of a CRM or a spiked sample):uncertainty in cert. value / STD of replicate analyses u ( Rm
Rm reprezintrecuperareaobtinu avândla baz analiza unui CRM sauo probacu adaos u ( R m):incertitudineavaloriicert./ STD a analizelorrepetate
R rep: correction factor for different in behaviour of analytein spike and real sample with incurred analyte
Rrep: factorde corec iepentrucomportareadiferitaanalituluiînprobe „spike“(cu adaosde analit)şiînprobe reale
The robustness (ruggedness) of the measurement procedureis the resistance to change in the result when minor deviationsare made from the experimental conditions described in theprocedure
Robusteteauneiproceduride msurarereprezintcapabilitateade schimbare arezultatuluiatuncicandsuntaplicatedevia ii micide la condi iileexperimentaledescriseînprocedur
Procedure prescribes the limits for experimental parameters
Procedura prescrie limite pentru parametrii experimentali
Parameter Values
Valoarea Parametrulu
Parameter Values
Valoarea Parametului
Identify variables of method: A,B, C, D etc
•Identificvariabilele metodei: A,B, C, D etc
Set-up experiments (Youden/Steiner)
•Incepeexperimentele (Youden/Steiner)
By systematic changing of one variable, determineeffects on result (see table Y/S)
•Schimbsistematico variabil, şideterminefectele asupra rezultatului (vezi tabel Y/S) pentru a determina
Procedure improvement from results obtained(gives also information on influence quantities)
•Imbunt eşteprocedurapebazarezultatelorob inute(ea oferde asemenea informa ii despremrimilede influen )
Experiment no.: Parameters AB C DEF G pH temp. reaction timereagent 1reagent 2age of column personnel Response
A B C DE F G pH temp. timp reactie reactiv 1 reactiv 2 coloana personal Raspuns
5 35 60 22 old xx v
5 35 60 22 noua xx v
7 25 30 22 old yy w
7 25 30 22 noua yy w
7 25 60 21 new x xx
7 25 60 21 noua x xx
7 35 30 12 new xx y
7 35 30 12 noua xx y
5 25 60 12 new yy t
7 35 60 11 noua yy z veche noua xx yy rt
Validation Report
Raportde Validare
Cadmium determination by GF-AAS
Determinarea cadmiului prin GF-AAS
Developed in-house to SI.Established by calibration Demonstrated bymeasurement of certifiedreference material-YYY
Dezvoltata ‘in-house’ la SI. Stabilita prin etalonare Demonstrata prin masurarea materialului de referintacertificat-YYY
• Intended Use:
• Scopul propus:
Screening of food samples
Urmarireaprobelorde alimente
• Typical Uncertainty:
• Incertitudinea
10%, see Uncertaintybudget (Annex)
10%, vezibudetulde incertitudine(Anexa)
• Analytical protocol:
•Protocol Analitic
Microwave digestion,followed by GF-AAS
Digestiecu microunde,urmatade GF-AAS
• Calibration:
• Etalonarea:
Name with solution standards from Supplier-ZZZ
Cu solutiietalon de la furnizorul-ZZZ
Head of Laboratory
•Domeniude lucru
Signature
Semnatura
Can I do the work?
Cazuri Practice ………
Cd in Milkexpected: 0.5 to 1.5 ng/g
Cd înlapteaşteptat: 0.5 to 1.5 ng/g
NO acceptable working range
NU � domeniul de lucru acceptabil
Cd concentration in lake watersexpected 5 - 10 ng/g
Cd înapa de lacuriaşteptat:: 5 to 10 ng/g
YES fit for purpose
DA�potrivit scopului
Traceability of Measurement results
Trasabilitatea Rezultatelor M sur rii
Scope of the lecture
Scopul prezent rii
•What is Traceability?•What is it needed for?•How to establish Traceability?•How to demonstrate Traceability?
• Ce este Trasabilitatea? • Pentru ce este necesar ? • Cum se stabileste Trasabilitatea? • Cum se demonstreaz Trasabilitatea?
Validation ( method fit-for-purpose ) www.NPL.co.uk
Validare (metoda este potrivit scopului ) www.NPL.co.uk
Quality of measurement result
Calitatea Rezultatului M sur rii
Uncertainty Budget
Bugetde Incertitudini
(How well I know the result )
(Cat de binestiurezultatulmsurrii)
Traceability of ...
Trasabilitatea ...
… measurement results … reference values
Esterelevantpentru;… rezultateale msurrii;… valoride referin
Traceability is a property of the result of ameasurement or the value of a standardwhereby it can be related to stated references,usually national or international standards,through an unbroken chain of comparisons allhaving stated uncertainties.
Trasabilitateaesteo proprietatea rezultatuluiuneimsurrisaua valoriiunuietalon de a puteafiraportatela referin e stabilite/ declarate,de regul,etaloanena ionalesauinterna ionale, prinintermediulunuilan neîntreruptde comparri,toateavândincertitudinistabilite.
Meaningful comparisons between measurements areonly possible if the results are expressed in the sameunits (measurement scale)
Comparrile semnificative între m sur ri sunt posibile numai dac rezultatele sunt exprimate în acelea ş i unit ide msur(scarde msurare)
•SI units (m, kg, s, A, K, mol, cd) or combination
•unit i SI (m, kg, s, A, K, mol, cd) saucombina ii
•to best internationally agreed reference (if no SI), suchas: delta scale for isotopic measurements pH scale the scale of octane numbers for petroleum fuel spectrophotometric measurement of lightness ofcoatings (CIELab system, Lovibond,…)
9msurareaspectrometrica reflectan eisuprafe elor (sistemul CIELab, Lovibond,…)
Do we really need traceability?
Avemnevoieîntr-adevr de trasabilitate?
Traceability to the samestated reference is of essential importance forcomparability of the results.
Trasabilitateala aceleaşireferin e stabilite/declarateestede o importan esen ialpentrucomparabilitatearezultatelor.
Comparability (able to compare) and reliability(trustworthiness) of measurement results betweendifferent laboratories are of outmost importance ifthey are to form an acceptable basis for decisionmaking and the implementation of regulations.
Comparabilitatea(capabilitateade a compara) şisiguran a (nevoiade încredere) înrezultatelemsurrilordintrediferitelaboratoaresuntde ceamaimare importan atuncicandeleformeazo bazacceptabilde luarea deciziilorşiimplementarea reglementrilor.
Stating & Establishing & Demonstrating … and I can show it
Declararea & Stabilirea & Demonstrarea … ş i pot sart
– – measurement proceduremodel equation
Specificarea m surandului d Alegerea corespunz toarea –proceduriide msurare–modeluluimatematic e
Demonstrating (validation) that:
Demonstrarea(validarea) c:
– the model equation is adequate (all significant influencequantities have been taken into account)
– modelulmatematicestecorespunztor(toatemrimilede influen semnificativeau fostluateînconsiderare)
– the measurement conditions are adequate
– condi iilede msuraresuntcorespunztoare f Stabilirea trasabilit ii pentrufiecaremrime de influen :–Alegereaetaloanelorde referin corespunztoare–Etalonareafolosindetaloanecorespunztoare g
Training in Metrology in Chemistry
Subiectulmsurriiex. colesterol
Validation and Traceability are “correlated” validation is part of establishing traceability
Validarea ş i Trasabilitatea sunt “corelate” validarea este o parteînstabilireatrasabilit ii
Traceability and Uncertainty are “correlated”“unbroken” chain of comparison & “unbroken” uncertainty propagation Slide 10
Trasabilitatea ş i Incertitudinea sunt “corelate” lan “neîntrerupt” de comparri & propagarea“neîntrerupt” a incertitudinii Slide 10
-2 m count
Nu mr
Associativity of Comparability –choosing reference standard
Asociativitatea Comparabilit tii – f alegerea standardelor de referin &
Are C
Sunt C
•established by calibration using appropriate standards
• stabilit prin etalonare folosind etaloane corespunz toare
Calibration:Set of operations which establish, under specified conditions, therelationship between values indicated by a measuring instrument -(including chemical steps) and the corresponding known values ofthe measurand.
Etalonarea: Set de opera ii care stabileste, in anumitecondi ii, rela iadintrevalorilemrimilorindicate de un instrument de msurare(incluzandetapeleanalitico-chimice) şivalorilecorespunztoarecunoscuteale msurandului.
Must be performed by reference standards with demonstratedtraceability and adequately small uncertainty.
Trebuiesafie efectuatprinintermediuletaloanelorde referin cu trasabilitate demonstrat ş i incertitudine corespunz toare mic.
Calibration Hierarchy iC iC iC iC
Ierarhia etalon rii
Tools
Mijloace
Traceability of Measurements
Trasabilitatea M surarilor
Value and uncertainty propagation
2 Valoare ş i propagarea incertitudinii
Idem for Certified RM
Identic pentru MR Certificate
Traceable to SI via Internationally recognised measurement capabilities
Lan & ul trasabilit ii Trasabilla SI via Capabilit i de msurarerecunoscuteinterna ional
CRM Production and certification producer
MRC Produc iesicertificare produc tor MRC
Value and uncertainty propagation ce
Valoare ş i propagarea incertitudinii sa
Result Traceable to Value of Reference Standard
Rezultattrasabilla valoarea Etalonului de Referin &
Sample Weighing
Cântarirea probei
Training in Metrology in Chemistry measurand: content of nitrate in plants suitable model equation validation (ILC, CRM) traceability certificates ofmanufacturer evaluate uncertainty
Demonstrarea Trasabilit & ii Training in Metrology in Chemistry cmsurand:con inutulde azotatdin plante d modelul matematic corespunz tor evalidare(ILC, CRM) f trasabilitate certificate ale producatorului g evaluarea incertitudinii
⋅ m st calibration(solution standard) using matrix CRM(determining R) gravimetry
R st folosirea MRC matriciale etalonare(solu iestandard) gravimetric
Uncertainty of Measurement Results
Incertitudinea Rezultatelor Msurrii
Uncertainty - what for?
•Incertitudine –pentru ce?
GUM procedure for uncertainty evaluation
•Procedura GUM de evaluare a incertitudinii
When should you evaluateuncertainties of measurement results ?
Cândtrebuie sevalua i incertitudinearezultatelor msurrii?
When a procedure is introduced inside your laboratory
•Atunci cândo procedureste introdusîn laboratorul Dvs.
When a critical factor changes in the procedure(instrument, operator, …)
•Atunci cândun factor critic este schimbat în procedurade msurare(instrument, operator, …)
•During / together with procedure validation
•In timpul / împreuncu validareaprocedurii
An individual evaluation process is NOT needed forevery individual result produced !
�NU este necesar un proces individual de evaluare a incertitudiniifiecruirezultat almsurrii!
ISO Definition of Uncertainty
Defini ia ISO a Incertitudinii
‘a parameter associated with the result of a measurement,that characterises the dispersion of the values that couldreasonably be attributed to the measurand ’
‘parametru, asociat rezultatului unei msurri, care caracterizeazîmprştiereavalorilor ce, în mod rezonabil, pot fi atribuite msurandului’
Result = Value ± uncertainty
Rezultat = Valoare ± Incertitudine
The value is between 17.9 and 27.5 mg/kg(cf. range, interval)
Valoarea este cuprinsîntre17.9 si 27.5 mg/kg (cf. domeniu, interval)
Why do we need uncertainty?
De ce avem nevoie de incertitudine? (1)
It is required by ISO 17025 - Accreditation
•Ea este cerutde ISO 17025 -Acreditare
The uncertainty of the result demonstrates the metrological QUALITY of the measurements (not measuring with the smallest achievable uncertainty)
•Incertitudinea unui rezultat demonstreaz CALITATEA metrologica msurrilor(nu msurareacu cea mai mic incertitudine realizabil)
In laboratory document in transparent way themeasurement procedure
• Pentru utilizator corespunz toare
•For end-user give the result with proper confidence•To allow comparison of results
•Permite compararea rezultatelor
Why do we need uncertainty ? (2)
De ce avem nevoie de incertitudine? (2)
A well documented uncertainty statement underpinsyour results and provides transparency!
O declarare de incertitudine bine documentatdîncredererezultatele şi confertransparent!
Identify major uncertainty contributors -find out ways to improve the procedure
Identificsurselemajoreale incertitudinii –gseştemodalit ilede îmbunt ire a procedurii
Demonstrate compliance with limits (legal orcontractual) and the establishment of acceptancecriteria
Demonstreazîncadrareaînlimite(legale sau contractuale) şifundamenteazcriteriilor de acceptare
Your best defence in discussions!
�Cea mai bunaprare a Dvs. îndiscu ii !
Repeating the measurement 2, 10 or 100 times doesnot give you all information to have reliable results!
:Repetarea de 2, 10 sau 100 de ori a msurrilornu vdtoate informa iilepentru a avea rezultate de încredere!
True Value orbest estimate of True Value
Valoarea Adevaratsaucea mai bunestima iea Valorii Adevrate
We can approach to measure the true value bymeasuring the “the best estimate” aiming to know true value
�încercândsa aflm valoarea adevrat
Are results different?
Sunt rezultatele diferite?
No results without uncertainty !
Nu rezultate fr incertitudine !
• GUM approach: uncertainty propagation (combined unc.)to take into account the contribution of all components
• Abordarea GUM : propagareaincertitudinii(inc. compus)pentrua luaînconsiderarecontribu iatuturorcomponentelor
No statistical tests required by GUM (almost) …/…cf. Visual comparison overlapping ranges Y/N ?
GUM (aproapec)nupretindetestestatistice…/…cf. compara iei vizuale � suprapunerea intervalului Da/Nu ?
Are these results different?
Sunt aceste rezultate diferite?
No uncertainty evaluation value
Dupevaluarea incertitudinii
After uncertaintyevaluation
Frevaluarea incertitudinii
(only precision)
(doar precizia)
GUM does not requirestatistical testsunless you need it …
GUM nu pretinde teste statistice doardactuai nevoie de ele …
“If it is deemed useful for the intended users of themeasurement result, ……, one may indicate - theestimated effective degree of freedom…” – [GUM 7.2.1] when comparing results for legal requirements requested by customer
“Dacse considerutil pentru utilizatorii rezultatului msurrii, ……, se pot preciza –gradele de libertate efectiv estimate …”–[GUM 7.2.1]
Don’t forget
0Nu uita!
What is new in GUM ?
Ce este nou în GUM ?
GUM is guide for a transparent, simple andstandardised documentation of the measurement procedure
GUM este ghidul pentru o documentare transparent, simpli şstandardizata proceduriide msurare
Using uncertainty evaluations, such as type A (measured in the lab) and type B (other)
Utilizânddiferitemodalittide evaluarea incertitudinii, precum tip A (msurriefectuatein lab)şi tip B (altele)
Do NOT use random & systematic errors ! •The use of Combined/expanded Uncertainty
•Utiliza i Incertitudinea Compus/Extins
Type A evaluation of uncertainty: statistical analysis of series of observations.
Evaluarea de Tip Aa incertitudiniianaliza statistica unei serii de observa ii.
Type A standard uncertainty is measured from repeatabilityexperiments and is quantified in terms of the standard deviation ofthe measured values
Evaluareade Tip A aincertitudinii: prinrepetareaexperimentelorşi estecuantificatcaabatereastandarda valorilor msurate
Type B evaluation of uncertainty:by other means than statistical analysis(previous experiments, literature data, manufacturer’s information)
Evaluarea de Tip Ba incertitudinii:prinalte mijloacedecât analiza statistic(experimente anterioare, date din literatur, informa iileproductorului)
Understanding the measurement !
Intelegerea msurrii!
“…The evaluation of uncertainty is neither a routinetask nor a purely mathematical one; it depends ondetailed knowledge of the nature of the measurandand of measurement…”
“…Evaluarea incertitudinii nu este nici o sarcinde rutinişnici una matematic; ea depinde de cunoastereadetaliata naturii msuranduluişia msurrii…”
Document the data you used as input for measurement!!
Documentati-vdatele utilizate ca intrripentru msurare!!
“…The pool of information may include:previous measurement data;validation data experience with or general knowledge of the behaviourand properties of relevant materials and instruments; manufacturer’s specificationsdata provided in calibration and other certificates; uncertainty assigned to reference data taken fromhandbooks”
9specifica ii ale productorilor;9date furnizate din etalonareşidin altecertificate;9incertitudinea atribuitdatelor de referin din manuale”9
What do you need to know ?
Ce trebuies ti i ?
•average of the set of data;
•media setului de date;
•standard deviation;
• abaterea standard;
The 10-steps GUM Sequence
Secven a celor 10-paşi GUM
1 - Define the Measurand
1 –Definirea msurandului
2 - Describe the Model Equation (for the measurement procedure)
2 –Descrierea Modeluluimatematic(pentru procedura de msurare)
3 - Identify (all possible) sources of uncertainty
3 -Identificarea(tuturorposibilelor) sursede incertitudine
4 - Evaluate all input quantities
4 -Evaluarea tuturormrimilorde intrare
5 - Evaluate the standard uncertainty (1s) of each input quantities
5 –Evaluarea incertitudinii standard (1s) a fiecreimrimide intrare
The 10-steps GUM Sequence
Secven a celor 10-pa ş i GUM
6 - Calculate the value of the measurand (using the equation model)
6 –Calculul valorii m surandului (utilizând Modelul matematic)
7 - Calculate the combined standard uncertainty of the result
7 –Calculul incertitudinii standard compusea rezultatului
8 - Calculate the expanded uncertainty (with a selected k)
8 –Calculul incertitudinii extinse (cu un k selectat)
9 - Analyse the uncertainty contribution index (THINK !!)
9 –Analiza indicilor-pondereaincertitudinilor(GANDESTE !!)
10- Document all steps in a Report.
10–Documentarea tuturor paşilorîntr-un Raport.
Sample treatment•Sample weighing, m•Extraction, R
Tratamentulprobei•Cântrireaprobei, m•Extrac ia, R
Determination of Nitrateby Ion Chromatographyin Plant material
Determinarea azota ilordin planteprin ion cromatografie
•Preparing the sample solution, VNO3-
• Aducerea probei în fazade solu ie, VNO3-
Preparing the standard solution, fdi solution, Cst
Preparareasolu iei etalon, Cst prob, fdi
Instrumental measurement, ANO3- measurement, Ast
M surarea instrumental, ANO3- instrumental, Ast
Calculation of the result, QNO3-
Calcululrezultatului,
Step 1 - Definition of “Measurand”
Pasul 1 -Definirea “Msurandului”
Example: content of NO in (mg/g)
(în mg/g)
Step 2 - Model Equation
Pasul 2 -Modelul matematic
The model of the measurement procedure is afunctional relation between input quantities andoutput quantity (result)
Modelul m surare m rimile (rezultat)
Measurement MODEL is the equation you usefor the calculation of your result !
MODELUL matematical msurriieste ecua iape care o utilizezi pentru calculul rezultatului tu!
What are input quantities?
Care sunt mrimilede intrare?
The output quantity Y depends on input quantities X
Mrimeade ie ş ire Y depinde de mrimilede intrare X
Input quantities (Xi) may be quantities whose value anduncertainty are directly determined in the current measurement (Type A, statistical analysis of series ofobservation) or brought into the measurement fromexternal sources (Type B, previous experiments, literaturedata, information from manufacturer )
Mrimilede intrare(Xi) pot fi mrimileale crorvalori şi incertitudinisunt determinate direct înmsurrile curente (Tip A, analiza statistica seriilorde observa ii) sau introduse încadrul masurriidin surse externe (Tip B, experimente anterioare, date din literatur, informa ii de la productor)
Model Equation
Modelul matematic
ANO3-Ast VNO3- m nitrate content of the sample (mg/g)nitrate concentration in standard solution (mg/l)peak area for sample solution peak area for standard solutionvolume of sample solution ( l )mass of the sample (g)dilution factor (no units);recovery factor (cf. sample preparation) fdi R
VNO3-m con inutulde azota i din prob(mg/g)concentra iade azota i în solu ia etalon (mg/l)aria picului pentru solu iade probaria picului pentru solu iaetalonvolumul solu ieide prob( l )masa probei(g)factorul de dilu ie(frunitti); factorul de recuperare (cf. preparriiprobei) fdi R
Step 3 - Possible Sources of Uncertainty
Pasul 3 –Surseposibile de incertitudine
Volume, VNO3
Volumul, V
Recovery, R
Recuperarea, R
Glassware Certificate balance calibration
Sticlaria certificata
Signal Stability balance calibration
Calibrarea balantei st
Standard, Ast
Stabilitatea semnalului
Instrument calibration
Calibrarea instrumentului
Collection of operations
Semnalul pentru
Step 4 - Input Quantities Uncertainty(evaluation type A & B) repeated observation (A) validation experiments (A and/or B) manufacturers’ specifications (B) calibration certificates (B) results of interlaboratory method validations (B) • • • • • • from experience and/or literature (B)
Pasul 4 –Incertitudinea mrimilorde intrare(evaluarea de tip A & B) •observa iirepetate(A)•validarea experimentelor (Aşi/sau B)•specifica iileproductorului(B)•certificate de etalonare(B)
Step 5 - Convert to Standard Uncertainties
Pasul 5 –Convertirea in Incertitudini Standard
Before combining, all uncertainty contributions must beexpressed/converted as “estimated” standard uncertainty when available as:
Inaintede compunere, toate componentelede incertitudinetrebuieexprimate/ convertiteînincertitudinistandard cândle avem sub forma:
–confidence intervals: convert
–intervale de încredere: se convertesc
See Module “Statistics”
Vezi Modulul “Statistic ”
Step 6 - Calculate Value of Measurand
Pasul 6 -Calculul Valorii Msurandului
Use model equation to calculate the value ofoutput quantity Y (QNO3-)
Se utilizeazmodelul matematicpentrua calcula valoarea mrimiide ieşire Y (QNO3-
Step 7 - Combined Standard Uncertainty
Pasul 7 –Incertitudinea Standard Compus